In a Long Term Evolution/Long Term Evolution Advance (LTE/LTE-A) system, a terminal demodulates a Physical Downlink Share Channel (PDSCH) and sends a Physical Uplink Share Channel (PUSCH) according to a Downlink Control Information (DCI) scheduling indicator which is sent by a base station through a Physical Downlink Control Channel (PDCCH), so as to complete receiving of downlink data and sending of uplink data.
Multiple DCI formats are defined in the LTE/LTE-A system; DCI Format 0 and DCI Format 4 can be used for uplink scheduling, and DCI Format 1, DCI Format 1A, DCI Format 1B, DCI Format 1C, DCI Format 1D, DCI Format 2, DCI Format 2A, DCI Format 2B, DCI Format 2C, DCI Format 3 and DCI Format 3A can be used for downlink scheduling. The transmitted control information includes some scheduling configuration parameters, and the scheduling configuration parameters are generally divided into resource configuration parameters and transmission configuration parameters, wherein the resource configuration parameters can be specifically resource block allocation parameters, and the transmission configuration parameters can be specifically carrier indicator, format identity, Modulation and Coding Scheme (MCS) level and Redundancy Version (RV), New Data Indicator (NDI), Transmit Power Control (TPC) command and so on.
In addition, for compromise of the control signalling overhead and the scheduling flexibility, in the LTE/LTE-A system, a synchronous adaptive or non-adaptive Hybrid Automatic Repeat Request (HARQ) mechanism is adopted for uplink, and an asynchronous adaptive HARQ mechanism is adopted for downlink, and the downlink DCI needs to include an HARQ process number of each data packet for differentiating. In a Frequency Division Duplexing (FDD) system, the supported maximum number of HARQ processes is 8, and the DCI includes 3 bits for indicating the process number used by the data packet. In a Time Division Duplexing (TDD) system, the supported maximum number of HARQ processes is 15, and the DCI includes 4 bits for indicating the process number used by the data packet.
In the existing LTE technology, two resource indicating ways for data transmission, namely dynamic scheduling and semi-static scheduling, are defined for data packet transmission of a same user. Under the dynamic scheduling, there is a piece of DCI corresponding to a transmission data block of each subframe. Under the semi-static scheduling, the base station sends the DCI only when the semi-static scheduling is started, and the terminal sends and receives new data packets at certain time intervals and using the same scheduling configuration parameter. In addition, a Transmission Time Interval (TTI) bundling scheme can also be adopted for uplink in the LTE system, but it is only transmission of different redundancy versions of a same data packet by multiple consecutive subframes, which influences the overall spectrum efficiency.
In some scenarios, such as a Small Cell (SC) and multi-user, multi-packet services, the factors restricting system capacity is mainly capacity of a control channel; if the dynamic scheduling is adopted, each data packet of each user needs a piece of DCI corresponding thereto, which inevitably needs high control signalling overheads and occupies a lot of valuable resources; even an Enhanced Physical Downlink Control Channel (ePDCCH) is used, there is still the problem of high control signalling overheads; if the semi-static scheduling is used, the scheduling flexibility is poor.